If you can’t see another extension after following the instructions you should follow these steps:

Unplug the device from your Mac

Go to Applications -> Utilities -> Audio MIDI Setup

In the menu bar click Windows -> MIDI Studio

Select D400 and Remove device

Restart the Mac

Plug the device back in

Volume ring blinks and device does not respond

This means that your device is in firmware update mode. This might happen if an update was interrupted. To restore normal functionality, you have to open the Asparion Configurator and start the firmware update again.